Nicolae Simionescu Institute Of Cellular Biology And Pathology

Bucharest, Romania

Nicolae Simionescu Institute Of Cellular Biology And Pathology

Bucharest, Romania

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Uritu C.M.,Petru Poni Institute of Macromolecular Chemistry | Calin M.,Nicolae Simionescu Institute of Cellular Biology and Pathology | Maier S.S.,Petru Poni Institute of Macromolecular Chemistry | Maier S.S.,Technical University Gheorghe Asachi | And 7 more authors.
Journal of Materials Chemistry B | Year: 2015

Transfection of nucleic acid molecules, large enough to interfere with the genetic mechanisms of active cells, can be performed by means of small carriers, able to collectively collaborate in generating cargocomplexes that could be involved in passive mechanisms of cellular uptake. The present work describes the synthesis, characterization, and evaluation of transfection efficacy of a conjugate molecule, which comprises a cyclic siloxane ring (2,4,6,8-tetramethylcyclotetrasiloxane, cD4 H) as the core, and, on average, 3.76 molecules of 2 kDa polyethyleneimine (PEI) as cationic branches, with an average molecular mass of 7.3 kDa. As demonstrated by in silico molecular modeling and dynamic simulation, the conjugate molecule (cD4 H-AGE-PEI) tends to adopt an asymmetric structure, specific for amphipathic molecules (confirmed by a log P value of -1.902 ± 0.06), that favors a rapid interaction with nucleic acids. The conjugate and the polyplexes with the pEYFP plasmid were proved to be non-cytotoxic, and capable of ensuring transfection yields better than 30%, on HEK 293T cell culture, superior to the value obtained using the SuperFect® reagent. We presume that the increased transfection efficacy originates in the ability of the conjugate to locally tightly encompass pDNA molecules by electrostatic interaction mediated by the short PEI branches, and consequently to expose the siloxane hydrophobic moiety, which decreases the interaction energy with the lipid layers. © The Royal Society of Chemistry.


PubMed | Centers for Disease Control and Prevention, Bacau County Emergency Hospital, Cantacuzino National Institute of Research Development for Microbiology and Immunology, University of Groningen and 7 more.
Type: Journal Article | Journal: PloS one | Year: 2015

This study presents the first characterization of carbapenem-non-susceptible Klebsiella pneumoniae isolates by means of a structured six-month survey performed in Romania as part of an Europe-wide investigation. Klebsiella pneumoniae clinical isolates from different anatomical sites were tested for antibiotic susceptibility by phenotypic methods and confirmed by PCR for the presence of four carbapenemase genes. Genome macrorestriction fingerprinting with XbaI was used to analyze the relatedness of carbapenemase-producing Klebsiella pneumoniae isolates collected from eight hospitals. Among 75 non-susceptible isolates, 65 were carbapenemase producers. The most frequently identified genotype was OXA-48 (n = 51 isolates), eight isolates were positive for blaNDM-1 gene, four had the blaKPC-2 gene, whereas two were positive for blaVIM-1. The analysis of PFGE profiles of OXA-48 and NDM-1 producing K. pneumoniae suggests inter-hospitals and regional transmission of epidemic clones. This study presents the first description of K. pneumoniae strains harbouring blaKPC-2 and blaVIM-1 genes in Romania. The results of this study highlight the urgent need for the strengthening of hospital infection control measures in Romania in order to curb the further spread of the antibiotic resistance.


Albu M.G.,INCDTP Division Leather and Footwear Research Institute | Titorencu I.,Petru Poni Institute of Macromolecular Chemistry | Titorencu I.,Nicolae Simionescu Institute of Cellular Biology and Pathology | Chelaru C.,INCDTP Division Leather and Footwear Research Institute
Leather and Footwear Journal | Year: 2011

Hydrogel dressings are cross-linked polymer gels that are often shaped into sheets to provide and maintain a moist environment on site of wound application. Biological hydrogels are widely used as cell-culture substrates because of their resemblance to the natural extracellular matrix and complex signaling which facilitate the adhesion and growth of cells. In this study the collagen gels were cross-linked with glutaraldehyde in order to obtain a stable structure without any cytotoxic effects. The obtained hydrogels were characterized by thermal analysis, FT-IR spectroscopy, as well as enzymatic degradation and their biocompatibility with endothelial cells was monitored by optic and fluorescence microscopy. The hydrogels cross-linked with 0.4-1.0% did not show any cytotoxic effect in contact with endothelial cells. The hydrogel with 1.2% collagen and 0.8% GA is the most stable and could be a basic promising biomaterial for tissue engineering and drug delivery systems.


Liakos I.L.,Italian Institute of Technology | Grumezescu A.M.,Polytechnic University of Bucharest | Holban A.M.,Polytechnic University of Bucharest | Holban A.M.,University of Bucharest | And 5 more authors.
Pharmaceuticals | Year: 2016

Polylactic acid was combined with lemongrass essential oil (EO) to produce functional nanocapsules (NCs). The obtained polylactic acid nanoparticles showed antimicrobial activity both with and without the presence of lemongrass oil; however, the presence of EO improved the activity of the NCs. The presence of lemongrass assisted the formation of well-separated NCs and also provided enhanced antimicrobial properties, since lemongrass is known for its antimicrobial character. Fluorescence microscopy was used to optically observe the nanoparticles and NCs and revealed the attachment of lemongrass oil with the polylactic acid NCs. Dynamic light scattering was used to determine their size. UV absorption was used to determine the exact amount of lemongrass oil found in the polylactic acid-lemongrass oil NCs, which was important for understanding the minimum inhibitory concentration for the antimicrobial experiments. A series of clinically important microbial species were used in the study and the obtained NCs proved to have very good antimicrobial properties against all tested strains. Such NCs can be used for the design of ecological strategies, based on natural alternatives, which may be efficient against severe infections, including those that involve resistant pathogens and biofilms or those with difficult to reach localization. © 2016 by the authors; licensee MDPI, Basel, Switzerland.


Ana Maria R.,Nicolae Simionescu Institute Of Cellular Biology And Pathology | Alexandrina B.,Nicolae Simionescu Institute Of Cellular Biology And Pathology
Annals of the Romanian Society for Cell Biology | Year: 2015

Recent studies showed that culture of mesenchymal stem cells (MSC) as three-dimensional (3D) aggregates enhanced their therapeutic potential. The aim of this study was to determine the changes associated to MSC aggregation, with particular focus on multipotency and microRNA expression patterns. To this aim, MSC isolated from adult mouse bone marrow were aggregated by incubation in hanging drops for 72h. The aggregates were cultured on gelatin-coated plates to generate explants, which were either analysed for microRNA expression pattern (using TaqMan MicroRNA Assays and miRWalk and Panther databases) or dissociated and re-cultured for multipotency assessment. The results showed no difference between the differentiation capacity of explanted and normal cultured MSC. However, microRNA expression pattern revealed the induction of three microRNAs (miR-380-5p, 434-5p and 302c) as well as an overall increased microRNA expression level (1.6 fold versus control). In silico analysis of these microRNAs suggested the activation of several cellular processes involved in engraftment, such as biological adhesion, response to stimulus and prevention of ECM proteins degradation, as well as inhibition of apoptosis in explanted MSC versus control. By concluding, 3D aggregation of MSC did not affect their multipotency, yet induced changes which might impact the resistance and behaviour of cells post-transplantation. © The Romanian Society for Cell Biology.


Manea A.,Petru Poni Institute of Macromolecular Chemistry | Manea A.,Nicolae Simionescu Institute of Cellular Biology and Pathology
Cell and Tissue Research | Year: 2010

Reactive oxygen species (ROS) are essential mediators of normal cell physiology. However, in the last few decades, it has become evident that ROS overproduction and/or alterations of the antioxidant system associated with inflammation and metabolic dysfunction are key pathological triggers of cardiovascular disorders. NADPH oxidases (Nox) represent a class of hetero-oligomeric enzymes whose primary function is the generation of ROS. In the vasculature, Nox-derived ROS contribute to the maintenance of vascular tone and regulate important processes such as cell growth, proliferation, differentiation, apoptosis, cytoskeletal organization, and cell migration. Under pathological conditions, excessive Nox-dependent ROS formation, which is generally associated with the upregulation of different Nox subtypes, induces dysregulation of the redox control systems and promotes oxidative injury of the cardiovascular cells. The molecular mechanism of Nox-derived ROS generation and the means by which this class of molecule contributes to vascular damage remain debatable issues. This review focuses on the processes of ROS formation, molecular targets, and neutralization in the vasculature and provides an overview of the novel concepts regarding Nox functions, expression, and regulation in vascular health and disease. Because Nox enzymes are the most important sources of ROS in the vasculature, therapeutic perspectives to counteract Nox-dependent oxidative stress in the cardiovascular system are discussed. © Springer-Verlag 2010.


Fenyo I.M.,Nicolae Simionescu Institute of Cellular Biology and Pathology | Florea I.C.,Nicolae Simionescu Institute of Cellular Biology and Pathology | Raicu M.,Nicolae Simionescu Institute of Cellular Biology and Pathology | Manea A.,Nicolae Simionescu Institute of Cellular Biology and Pathology | Manea A.,Petru Poni Institute of Macromolecular Chemistry
Vascular Pharmacology | Year: 2011

Oxidative stress-induced vascular injury represents a major contributor to the pathoetiology of atherosclerosis. Elevated NADPH oxidase (Nox) activity promotes oxidative injury of the cardiovascular cells. Janus-tyrosine-kinase (Jak) family regulate various aspects of the atherosclerotic process e.g., inflammation, cellular growth, proliferation, and migration. Here, we investigated the potential of Jak2 inhibition to counteract Nox-dependent O2 •- formation in atherogenesis in hypercholesterolemic apolipoprotein E-deficient (ApoE-/-) mice. Male ApoE-/- mice fed a high-fat, cholesterol-rich diet were treated for 5weeks with either vehicle or tyrphostin AG490 (1mg/kg), a specific Jak2 inhibitor. Lucigenin-enhanced-chemiluminescence assay, real-time PCR and Western blot analysis revealed that Nox-derived O2 •- generation, Nox1, Nox2, and Nox4 mRNA and protein levels were significantly elevated in the aortas of ApoE-/- mice fed a high-fat diet compared to ApoE-/- mice fed a normal diet. Treatment with tyrphostin AG490 significantly reduced the up-regulated Nox activity, the expression of each Nox subtype, as well as the protein level of CD68, a macrophage-specific marker. Morphometric analysis showed a marked reduction of atherosclerotic lesions in the aorta of AG490-treated animals. These data provide new insights into the regulation of vascular Nox by tyrphostins in the cardiovascular system. Since Jak2 transduces the signals of various cardiovascular risk factors, pharmacological manipulation of this signaling pathway may represent a novel strategy to reduce oxidative stress in atherosclerosis. © 2011 Elsevier Inc.


Raicu M.,Nicolae Simionescu Institute of cellular biology and pathology | Manea A.,Nicolae Simionescu Institute of cellular biology and pathology | Manea A.,Petru Poni Institute of Macromolecular Chemistry
Annals of the Romanian Society for Cell Biology | Year: 2010

Oxidative stress plays a key role in the onset and progression of atherosclerosis. Hyperactivity of the NADPH oxidase (Nox) promotes oxidative injury of the vascular cells. The molecular mechanisms of Nox regulation are not entirely elucidated. Activator protein-1 (AP-1) regulates various aspects of the atherosclerotic process such as inflammation, cellular growth, proliferation, and migration. In this study we have investigated the role of AP-1 in the regulation of Nox1 and Nox4 isoforms transcription in human aortic smooth muscle cells (SMCs). Cultured cells were exposed for 24 hours to tumor necrosis factor-α (TNFα), a potent inducer of AP-1. Lucigenin-enhanced chemiluminescence, real-time polymerase chain reaction, and Western blot analysis showed that inhibition of AP-1-related pathway reduced significantly the TNFα-dependent up-regulation of Nox-derived O 2 •- production, Nox1 and Nox4 expression. In silico analysis indicated the existence of typical AP-1 elements in the promoters of human Nox1 and Nox4 genes. Transient overexpression of c-Jun/AP-1 significantly increased the promoter activities of both isoforms. These data demonstrate that AP-1 transcription factor is an important regulator of Nox1 and Nox4-containing NADPH oxidase expression and function in human aortic SMCs. Because AP-1 transduces the signals of various cardiovascular risk factors, pharmacological manipulation of this signaling pathway may represent a novel strategy to reduce oxidative stress in atherosclerosis.


Manea A.,Petru Poni Institute of Macromolecular Chemistry | Manea A.,Nicolae Simionescu Institute Of Cellular Biology And Pathology | Fenyo I.M.,Nicolae Simionescu Institute Of Cellular Biology And Pathology | Florea I.C.,Nicolae Simionescu Institute Of Cellular Biology And Pathology | Raicu M.,Nicolae Simionescu Institute Of Cellular Biology And Pathology
Annals of the Romanian Society for Cell Biology | Year: 2010

Hyperactivity of the NADPH oxidases (Nox) associated with alterations in the antioxidant system triggers oxidative-stress-induced vascular dysfunction and initiates the chain of events that contributes to diabetes-associated cardiovascular disorders. Hitherto, the role of individual Nox isoform in high glucose-induced reactive oxygen species (ROS) formation in the vascular cells has not been elucidated. Employing small interfering RNA (siRNA) technology we have investigated the contribution of each Nox subtype in the upregulation of ROS in human aortic smooth muscle cells (SMCs) maintained in diabetic conditions. Cultured cells were exposed for 8, 24, and 48 hours to either normal (5 mM) or high glucose (25 mM) concentrations. Lucigenin-enhanced chemiluminescence and dichlorofluorescein assays demonstrated that high glucose increases the Nox activity and intracellular ROS production. Real-time PCR and Western blot analysis demonstrated that transfection of SMCs with Nox1/4/5-trageted siRNA resulted in a significant decrease of the mRNA expression and protein levels of each Nox isoform. Knock-down of Nox1 and Nox4 greatly reduced the high glucose-dependent up-regulation of Nox activity and ROS production. Transient down-regulation of Nox5 expression did not affect significantly the elevated oxidative status. These data provide new insights into the regulation of vascular Nox by high glucose in vascular SMCs. In this context, modulation of various Nox isoforms may represent a novel and efficient pharmacological strategy to attenuate the pathological effects of oxidative stress in diabetes-associated cardiovascular disorders.


PubMed | Nicolae Simionescu Institute of Cellular Biology and Pathology, Italian Institute of Technology and Polytechnic University of Bucharest
Type: Journal Article | Journal: Pharmaceuticals (Basel, Switzerland) | Year: 2016

Polylactic acid was combined with lemongrass essential oil (EO) to produce functional nanocapsules (NCs). The obtained polylactic acid nanoparticles showed antimicrobial activity both with and without the presence of lemongrass oil; however, the presence of EO improved the activity of the NCs. The presence of lemongrass assisted the formation of well-separated NCs and also provided enhanced antimicrobial properties, since lemongrass is known for its antimicrobial character. Fluorescence microscopy was used to optically observe the nanoparticles and NCs and revealed the attachment of lemongrass oil with the polylactic acid NCs. Dynamic light scattering was used to determine their size. UV absorption was used to determine the exact amount of lemongrass oil found in the polylactic acid-lemongrass oil NCs, which was important for understanding the minimum inhibitory concentration for the antimicrobial experiments. A series of clinically important microbial species were used in the study and the obtained NCs proved to have very good antimicrobial properties against all tested strains. Such NCs can be used for the design of ecological strategies, based on natural alternatives, which may be efficient against severe infections, including those that involve resistant pathogens and biofilms or those with difficult to reach localization.

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